Process of recovering ammonia from gases.



H. KOPPEBS. V

PROCESS OF B-ECDVERIKG AMHDKIA PRO! APPLICATION FILED JUL! 22, 191B.

Patented Jan. 2, 1912.

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m E S W-Ffnessea H'TEINBICH KOPPERS, OF ESSEN, GERMANY.

PROCESS OF EEOOVERING AMMONIA FROM GASES.

Specification of Ictters Patent.

Patented Jan. 2,1912.

Application filed July 22, 1910. Serial No. 573,166.

To all wlwm itmay concern? Be it known that I, HEI RI H Korrsns,residingnt Essen, Germany, and a citizen of Gennan'y, have invented anew and use-' 6 ful ocess of Recovering Ammonia from Gases, of.wh1cl1the following isa specification.

This invention relates to a process-of recovering ammonia from gasesgenerated by thedry distillation or gasilrcstion of fuel, and its objectis to provide means whereby the so-called fixed ammonimt. e. ammoniacombined with acids, is obtained without the addition of lime asheretofore gener- 5 all practiced. It is well known that besi es causingdiliiculties in working, the lime has the disadvantage of formingnoxious waste water. If the gas containing fixed ammonia is passed intothe saturator, hydrochloric acid is set free .which energeticallyattacks the pipes and appliances.

According to the present invention the ammonia compounds are separatedb? washing the gases with hot water or witi a hot solution of ammoniumehlorid, when the gases have a temperature near the dewpoint ofwater-saturation (approximately 80 (1.). The resultant ammonium chloridsolution is continuously reused, a portion being drawn oil and treatedfor the separation of fixed ammonia. This treatment of the solution mayconsist in evaporation of the solvent, to separate .the chlorid ofammonium as a commercial article, or the hydrochloric acid-ma beexpelled b adding sulfuric acidto the solution. T us by the treatment ofthe fixed ammonium'lcom-q pounds aswell as by that of the freeiitmmonia,there is formed ammonium sulfate, which ma -be added togethenin theform.

of a liqui or as a solid salt. a

-The' accompanying drawin represents an elevation of an apparatusor'carrying out my invention.

' The gases flowing through pipe 10 to washer 11 are freed 111 thelatter from fixed ammonia, by the action of hot water dis chargedfrom'pipe 12. This water is converted into s. gradually enriched brineby repeatodfreusejwith fresh gases; said p inf nhielly ammonium chlorid.QIL-l liquid flows througha pi 1-3 inton'sump teale1 1, whence. it is renrnedtb 1nshor 911 by a pump 15, thus continuous circulation. The ifixed ammonia flow "'Icla first washing thegases near, the dew Jointthrough pipe 16 intoc ooler l7, and are then force by pump 18 through atar-separator 19. The gases which are thus also from from tar are nowreheatedjn a super' heater 20 and conveyed. -to a siatnrator :21. Herethe gases are caused to give off their residual ammonia in the formsolid ammonium sulfate. The gases pass out of the saturator through pipe22, the salt heingfefl withdrawn through pipe -29. A' pipe 23communicating with pipe 12 receives part, of the salt-solution pum edfrom tank-l4, and delivers it to a. vesse 24, to which sul furic acid issupplied from pipe 28. This mixture is heated by steam-coi 25, thusyielding ammonium sulfate. The latter in solution is h pipe 26' conveyedto the saturator 2i, while the residual vapors (bcing mainly vaporsofhydrochloric acid) 75 leave vessel 24 through a pipe 2? without comingintocontaet with the main strelini f of gas. These vapors may bedischarged into the atmosphere, or may he utilized if desired.' Y

With the temperature maintained in the Washer 11, most of the tar iscondensed into a fog and floats within the gases, while thefixedammonium comppunds are in a solidform. Only a small proportion. ofmonia is absorbed during the washingwith the hot liquid, thepahsorbingcapaeityof said liquid for ammonia. being limited and, noundesirahlecooling of the taking. place. The waterlost from tie brine byeve oration in'the com-5: 0! circulation is pi-e erably I replaeedwhenever by slightly lowering the temporu'tiizpfinioiasl er 11; 'so';that part of the water. minisd. in the;gas e s is precipitatedtherefrom.

1m: 1:- The processof rmmvcring free and com;

'bined ammonia frnm gases-produrml in the dry distillation offuels,whicheonsists of water saturation-with n circulating dy ofxwater,thusio'r' Resolution contain ingthe fixed ammonia rom saidgilscsironducting'the said washed gssesto a stature-.1. tion bath containing sulfui'ie acid, 'troat'rn the solution of tlwll'xedennuonia Withfsu "i acidat a temperature snfiicienttodiiiye oil other acids contained therein,and eon- :1

veyin the solutionf otanunonium. sulfate thus 0 mined, into saidsaturation bath; j. 2. The prooessof recovering freenndoom- 1 binedammonia from gases produced in the dry distillation-of fuels, whichconsists in first washing the gases near the dew point of watersaturation with a circulating body of water, thus forming a solutioncontaining the fixed ammonia from said gases, conducting the said ;\wushed gases to a saturation 'bath 'oontaining sulfuric acid, treating thesolutionof the'fixedlarnmon-ia with sulfuric acid at a temperaturesuflicient to drive off other acids cont ained therein, and convey ingthe ammonium sulfate thus obtained into said saturation bath.

3. The process of recovering free and combin ammonia. from gasesproduced in the 15 dry" distillation of fuels, which consists in firstwashing the gases near the dew point'of l water saturation with acirculating body of solution of the fi-iied ammonia with so furic.

acid at. a temperature sufiicient to drive ofi? other acids containedtherein, and conveyin the ammonium sulfate thus produced an which stillcontains acid into said saturationbath.

HEINRICH KOPPERS. 1 s.]

Witnesses:

CHAS. J. \Vnmn'r, WALTER VONNEGUT.

